A249342 Position of the first occurrence of n-th noncomposite number, A008578(n), in A249337; positions of records in A249072.

1, 2, 6, 13, 20, 39, 45, 70, 80, 97, 121, 145, 193, 240, 257, 296, 322, 379, 400, 432, 481, 490, 532, 566, 632, 715, 760, 766, 807, 835, 878, 1067, 1104, 1209, 1215, 1369, 1414, 1468, 1514, 1540, 1605, 1683, 1706, 1853, 1871, 1905, 1935, 2116, 2276, 2293, 2304, 2343

Offset

1,2

Links

Table of n, a(n) for n=1..52.

Formula

For all n >= 1:

A249337(a(n)) = A008578(n).

A249072(a(n)) = n-1.

For all n >= 2:

a(n) = A249341(n) - 1.

Prog

(Scheme, with Antti Karttunen's IntSeq-library, two alternative definitions)
(define A249342 (MATCHING-POS 1 1 (lambda (n) (or (= 1 n) (and (= 1 (A249337 (+ 1 n))) (prime? (A249337 n)))))))
(define A249342 (RECORD-POS 1 1 A249072))

Crossrefs

After the initial term, one less than A249341.

Cf. A008578, A249337, A249340, A249072.

Sequence in context: A030416 A353588 A353971 * A006284 A048072 A215246

Adjacent sequences: A249339 A249340 A249341 * A249343 A249344 A249345

Keyword

nonn

Author

Antti Karttunen, Oct 26 2014

Status

approved